1. Field of the Invention
This invention relates to window devices that use electronically controlled liquid crystal material to selectively modify the transparency of the otherwise transparent window material. More specifically, this invention relates to window devices that use electronically controlled liquid crystal material that provides control of the transparency by application of a phase-controlled, frequency modulated current.
2. Description of Related Art
Several transparency control devices for windows and/or liquid crystal window devices are known in the art. Generally, these systems do not provide for user-controlled transparency and do not provide maximum transparency when current/voltage is withdrawn. Moreover, prior devices do not tend to provide the capability of polarizing light to reduce glare.
Although the following may not constitute prior art to this invention, the reader is referred to the following products and U.S. patent documents for general background material. Each of these patents and other documents are hereby incorporated by reference in its entirety for the material contained therein.
Techniver Glass, of Belgium, has proposed a product identified as S.G.G. PrivaLite that is not transparent in its native state and requires a properly controlled voltage to be applied in order to achieve 70% transparency.
Pilkington Glass, of the United Kingdom, has proposed an externally applied Electro-Chromic coating called “Pilkington E Control Glass,” which once the film has been applied to the exterior surface of properly prepared glass, the glass turns deepening shades of blue or other colors, as increasing amounts of voltage are applied across its surface.
M. Scalora, et al., published an article in the American Institute of Physics Journal of Applied Physics entitled Transparent, Metallo-Dielectric, One-Dimensional, Photonic Band-Gap Structures, which numerically describes the properties of metallo-dielectric, one-dimensional, photonic band-gap structures, Journal of Applied Physics, Vol. 83, No. 5, pp. 2377-2383 (1 Mar. 1998).
U.S. Pat. Nos. 4,091,610, 4,247,929 and 4,270,199 describe a thin-film transparent electrode provided on the front glass of an electronic wristwatch.
U.S. Pat. No. 4,582,395 describes an active matrix assembly for a liquid crystal display device utilizing an MIS transistor array.
U.S. Pat. No. 4,952,783 describes a flexible heater panel that comprises a light transmitting film substrate and a transparent conductive layer vacuum deposited on the substrate.
U.S. Pat. No. 5,096,801 describes a color image recording method that comprises exposing to light a light-sensitive material.
U.S. Pat. No. 5,143,979 describes a molding material suitable as an optical material and an optical recording medium.
U.S. Pat. No. 5,519,565 describes an electromagnetic-wave-modulating capacitors with movable electrodes for employment in highly transparent, conductive fixed electrodes.
U.S. Pat. Nos. 5,629,054 and 6,096,389 describe methods for continuously forming a functional deposited film of a large area with a microwave plasma-assisted CVD method.
U.S. Pat. No. 5,880,202 describes a black coating composition that comprises a light-screening material and macromolecular material.
U.S. Pat. No. 5,907,427 describes a photonic band gap structure device and method for delaying photonic signals of a predetermined frequency and a predetermined bandwidth by a predetermined delay.
U.S. Pat. No. 6,057,878 describes a three-dimensional picture image pickup apparatus.
U.S. Pat. No. 6,262,830 B1 describes a transparent metal structure that permits the transmission of light over a tunable range of frequencies.
U.S. Pat. No. 6,304,366 B1 describes a SH generator based on a photonic band gap (PBG) mixed half-quarter-wave, periodic structure.
U.S. Pat. No. 6,339,493 B1 describes a device and method of optics propagation and signal control integrated with micro-electro-mechanical-switches.
U.S. Pat. Nos. 6,343,167 B1 and 6,396,617 B1 describe a photonic band gap structure device and method for delaying photonic signals of a predetermined frequency and a predetermined bandwidth by a predetermined delay.
U.S. Pat. No. 6,414,780 B2 describes the non-linear reflectivity and non-linear transmissivity of a first photonic signal incident on a photonic band gap structure that is controlled by applying a second photonic signal to the structure.
U.S. Pat. No. 6,468,676 B1 describes an organic electro luminescent display element.
U.S. Patent Application Publication No. Us 2002/0021479 A1 describes an LCD device for displaying an image that includes pixel control electrodes constructed as a transparent metal stack having a photonic band gap structure that transmits a visible range of wavelengths and suppresses a non-visible range of wavelengths.